Machinery typically vibrates as it operates. The vibration can cause problems, for example mechanical damage, reduced efficiency of operation, increased noise and discomfort for persons in the vicinity of the machine. For example, in a nautical vehicle such as a ship, excessive vibration from the ship's engines can make travel in the ship uncomfortable.
It is known to use active machinery raft isolation mounts to control vibrations resulting from the operation of machinery. However, machinery is typically coupled to its environment in ways additional to the coupling through the machinery's mounting, for example by flexible couplings associated with exhaust, cooling, fuel and power supply systems. Such couplings and other connections provide additional paths for vibrations to propagate from the machinery, even if no vibrations were coupled across the mounts.
Wölfel Beratende Ingenieure GmbH+Co. KG produces an active absorber (ADD.Pipe) for the reduction of vibrations in pipes in piping systems in chemical plants and power plants. Vibrations in such systems are typically caused by water or other liquid hammers, pressure pulses or other excitations. The ADD.Pipe system is a collar that is clamped onto the piping system and includes a sensor that measures vibrations in the pipe and linear actuators actively controlled to move reaction masses to damp the vibrations in the pipe. However, the system offers only limited control, and has the potential to suffer from an effect known as pinning, in which vibration at the point of attachment of the collar is reduced but becomes worse at points elsewhere in the pipeline.
It would be advantageous to provide an apparatus, including an active vibration suppressor, in which one or more of the aforementioned disadvantages is eliminated or at least reduced.